FS-945 Digi International, FS-945 Datasheet - Page 52

• Manufacturer Part Number: FS-945
• Description: JTAG-BOOSTER FOR ELANSC400 3.3V
• Manufacturer: Digi International
• Series: Digi/FS Forthr
• Type: FLASHr

Specifications of FS-945

• Contents: Programmer and Associated Interface Software
• For Use With/related Products: AMD ElanSC400, SC410, 3.3V
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

3. Implementation Information
This chapter summarizes some information about the implementation of the
JTAG-Booster and describes some restrictions.
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The JTAG-Booster uses the EXTEST function of the JTAG-Interface to
perform Flash programming.
Connect the signal BNDSCN_EN to Pin 4 of the connector for the JTAG-
Booster. Please note: The signal BNDSCN_EN of the AMD ÉlanSC400 is
not 5V tolerant. If you power the JTAG-Booster with 5V (Pin 8 = +5V, Typ
227) there must be a protection circuit to protect the pin. On the FS FORTH-
SYSTEME module Élan486 there is a level shifter for the BNDSCN_EN
signal and the standard 5V version of the JTAG-Booster can be directly
connected to the module.
The signal BNDSCN_EN switches the AMD ÉlanSC400 complete to JTAG
test mode and normal operation is disabled. Therefor it is not possible to
observe CPU signals via JTAG interface while the CPU is running. (The
functions /SAMPLE and /SNAP are not available.)
ROMCS2 as a chip select to a memory device is not supported with an
separate option, because ROMCS2 can be mapped to any of the general
purpose chip select signals (GPIO_CSxx). If you want to use a memory
device connected to any of this GPIO_CSxx, you must set the default level of
this pin to Out,Lo in the file JTAGEL4.INI and must specify the option
/NOCS in the command line.
Most designs with the AMD ÉlanSC400 need a data buffer to separate the
DRAM from the ISA-Bus and boot ROM. This buffer is controlled with the
signals GPIO_CS4 (DBUFOE#), GPIO_CS3 (DBUFRDH#) and GPIO_CS2
(DBUFRDL#). If your design doesn’t have this data buffer and you have
connected other components to GPIO_CS2..4 you must specify the option
/NOBUFF to switch off the generation of the control signals.
JTAGEL4c.doc